BACKGROUNDTreatments to regenerate different tissue involving the transplantation of bone marrow derived mesenchymal precursor cells are anticipated. Using an alternative methods, in vitro organotypic slice culture method, would be useful to transplant cells and assessing the effects. This study was to determine the possibility of differentiating human bone marrow precursor cells into cells of the neuronal lineage by transplanting into canine spinal cord organotypic slice cultures.

METHODSBone marrow aspirates were obtained from posterior superior iliac spine (PSIS) of patients that had undergone spinal fusion due to a degenerative spinal disorder. For cell imaging, mesenchymal precursor cells (MPCs) were pre-stained with PKH-26 just before transplantation to canine spinal cord slices. Canine spinal cord tissues were obtained from three adult beagle dogs. Spinal cords were cut into transverse slices of 1 mm using tissue chopper. Two slices were transferred into 6-well plate containing 3 ml DMEM with antibiotics. Prepared MPCs (1×10(4)) were transplanted into spinal cord slices. On days 0, 3, 7, 14, MPCs were observed for morphological changes and expression of neuronal markers through immunofluorescence and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSThe morphological study showed: spherical cells in the control and experiment groups on day 0; and on day 3, cells in the control group had one or two thick, short processes and ones in the experiment group had three or four thin, long processes. On day 7, these variously-sized processes contacted each other in the experiment group, but showed typical spindle-shaped cells in the control group. Immunofluorescence showed that PKH-26(+) MPCs stained positive for NeuN(+) and GFAP(+) in experimental group only. Also RT-PCR showed weak expression of β-tubulin III and GFAP.

CONCLUSIONSHuman bone marrow mesenchymal precursor cells (hMPCs) have the potential to differentiate into the neuronal like cells in this canine spinal cord organotypic slice culture model. Furthermore, these findings suggested the possibility that these cells can be utilized to treat patients with spinal cord injuries.

Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; physiology ; Cells, Cultured ; Dogs ; Humans ; Mesenchymal Stromal Cells ; cytology ; Spinal Cord ; cytology

BACKGROUNDThere are no clear guidelines on implant removal. Few have assessed the long-term outcomes of patients with implants left in-situ, or removed. Therefore, removal of implants after fracture fixation remains controversial.

METHODSIn this retrospective study, we reviewed 53 patients with implant for fracture fixation in-situ for more than 3 years. All patients were younger than 60 years. Quality of life of each patient was assessed with the Chinese (Hong Kong) validated Short Form-36 and the pain was assessed with visual analogue scale (VAS). All patients were clinically examined and plain radiographs were taken.

RESULTSThe total SF-36 score of the patients was not statistically different from the Hong Kong norm (P > 0.05). Mean score of VAS was 2.08. Thirty-three patients (62.3%) reported limited range of movement, 9 patients (17%) complained of cosmetic problems, and 10 patients (18.9%) complained of weakness. Clinically, 82.6% of patients had no scarring, 84.7% of patients had full range of movement and all had no tenderness on assessment. Radiologically, no abnormality was detected except for one patient with known avascular necrosis of the femoral head after screw fixation.

CONCLUSIONAs most patients were clinically and radiologically normal with quality of life scores comparable to the norm, removal of implants is not advisable as a routine practice.

Adult ; Bone Screws ; Elbow Joint ; diagnostic imaging ; surgery ; Female ; Humans ; Male ; Middle Aged ; Orthopedics ; methods ; Prostheses and Implants ; Radiography ; Retrospective Studies ; Tarsal Bones ; diagnostic imaging ; surgery ; Treatment Outcome

The zinc finger transcription factor Egr-1 is critical for coupling extracellular signals to changes in cellular gene expression. In the hippocampus and amygdala, two major central regions for memory formation and storage, Egr-1 is up-regulated by long-term potentiation (LTP) and learning paradigms. Using Egr-1 knockout mice, we showed that Egr-1 was selectively required for late auditory fear memory while short term, trace and contextual memory were not affected. Additionally, synaptic potentiation induced by theta burst stimulation in the amygdala and auditory cortex was significantly reduced or blocked in Egr-1 knockout mice. Our study suggests that the transcription factor Egr-1 plays a selective role in late auditory fear memory.